1. Field of the Invention
The present invention is related to electric horns, in more particular to electric horns which are light in weight and excellent in sound quality and may suitably be used for cars.
2. Description of the Prior Art
FIG. 1 shows the conventional electric horn.
(1) is an iron casing consisting of the 1st and 2nd cylindrical casings (2) and (3), i.e., casing having bottoms; casing (2) has a flange section (6) around its upper edge and also has casing (3), smaller in diameter, fitted to the hole in its bottom plane.
Solenoid coil (4) is placed inside of the casing (3) and at its axial center, iron piece (5) is positioned, forming an electromagnet containing the iron casing as the external magnetic circuit.
(7) is a diaphragm covering the open section of casing (1), and (8) is an armature fixed on diaphragm (7) against iron piece (5). (9) is an interrupter for intermittent excitation of the solenoid, and (10) is a resonant plate provided against diaphragm (7).
Intermittent excitation of the solenoid will cause armature (8) to hit iron piece (5) strongly and intermittently to make sounds of high intensity with the aid of the resonance effect given by the combination of diaphragm (7) and resonant plate (10).
With the conventional horn of such a structure, it is iron casing (1) that contributes most to the weight of product among the components. Thus, reduction in thickness of the material for casing (1) is most effective for the reduction in weight of the product, but some problems relating to magnetism and mechanical strength impose a restriction on the applicability of the thickness reduction.
Reduction of the horn in outer diameter is conceivable, but some problems relating to sound quality, etc. make this idea inapplicable. It is thus an extremely difficult technological object to reduce the product in size and weight lowering the level of sound quality, etc. In addition, since the conventional structure holds the flat-plate-shaped diaphragm (7) by employing the fixing ring (10') to clamp the edge of diaphragm (7) around the flange section (6), diaphragm (7) will be distorted with unfavorable effects on the sound quality, frequency, etc.
The present invention is directed to the provision of electric horns which are free from the above-mentioned defects.